A two-point calibration method Ph meter, electrode calibration (two-point calibration method) 1. Preparation ready cups of pure water each equipped with 250 ml (to ensure correction accuracy) beaker, and in which the first cup is poured into pH7 phosphate reagent mixing, pour a second cup pH4 potassium hydrogen phthalate reagent (or pH9 sodium tetraborate reagent depending on the user needs to be monitored, the general pH4 reagents), and stir with a stirring rod, to completely dissolve The third cup of pure water is used as the electrode cleaning 2 ph meter calibration procedure pH7 point correction: Place the electrode in phosphate pH7 mixed solution until a pH meter to display the value of a stable hold down the CAL / ENT key for three seconds. The display shows 'correction, please wait', while the display (5) starts flashing .14 seconds later, the display stops flashing and shows '6.86', at the same time, the display shows 'pH7- calibration is complete' At this point, PH7 calibration is complete Remove the electrode, placed in a beaker of pure water equipment to do the cleaning PH4 points or PH9 point correction: after cleaning the electrode into pH4 potassium hydrogen phthalate solution (or pH9 sodium tetraborate solution ph meter structure, depending on the user selection) to be displayed value stable pH meter. Press and hold the CAL / ENT key for three seconds, the display shows 'ph meter calibration using the method, please wait', at the same time display start flashing .14 seconds later, the display stops flashing and shows '4.01', at the same time, the display shows 'calibration is complete,' returned to normal after three seconds the display (if the user selected pH9 sodium tetraborate, the display shows '9.18'). After adjustment is completed after the board terminated pt100 PT100 temperature probe, it automatically temperature compensated. If the user calibration, the display shows 'sensor aging' ph meter production base, then the electrode is aging, dashing and I contact the company to replace the electrode (or other failure of unknown origin) electrode calibration 1. Buy a new reading is not stable, or calibration error cause the first point: there are air bubbles inside the electrode sensitive film or gel. Display thrown down firmly electrode to remove bubbles (like rejection thermometer like), usually the electrode placed upright 2. Why pH7.00 buffer calibration: (This phenomenon is mainly in the gel electrode LE438 and LE407) resolved 7.02 Reason: At this point the temperature of the buffer solution at about 20 ℃. Buffer pH with temperature changes. 7.00 is the buffer value at 25 ℃, 20 ℃ and should be at 7.02; one hundred percent of the pH meter can automatically correct the effect of temperature on the buffer to ensure accuracy. 3. pH6.86 buffer reason calibrated display 7.00: Choosing the wrong group buffer correct: Re-set the correct buffer group. Cause of the error when setting procedure see the operating manual for a second 4-point calibration: Calibration dropouts. Correction: calibration, just press 'cal' key, do not press any other key. Detailed steps as follows: Step 1 calibration, set the calibration buffer group (domestic b = 3; import b = 2) 2, the electrodes were inserted into the appropriate buffer, and then press the "cal" key 3 until the figure is no longer flashing, it will electrode with deionized water clean after inserting the second buffer, then still press "cal" button, wait for 4 digital no longer flashes, the calibration has been completed, can be measured 5. In the different samples, showed almost no change factor : poor contact electrode and instrumentation; or correct electrode is bad: After shutdown, reconnect the electrode and instrumentation; or replace the electrodes. Use ph meter, ph meter Zhoukou City, one hundred to one hundred technology provided by Changzhou Technology Limited. Changzhou Best Technology Limited (www.czbckj.com) strong, credible, in Changzhou, Jiangsu chemical instrumentation industry has accumulated a large number of loyal customers. The company better work attitude and continuous improvement will lead one hundred innovative ideas into technology and you hand into the brilliant, for a better future!